21508748269 has 2 divisors, whose sum is σ = 21508748270. Its totient is φ = 21508748268.

The previous prime is 21508748263. The next prime is 21508748377. The reversal of 21508748269 is 96284780512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19554666244 + 1954082025 = 139838^2 + 44205^2 .

It is a cyclic number.

It is not a de Polignac number, because 21508748269 - 2¹⁹ = 21508223981 is a prime.

It is a super-2 number, since 2×21508748269² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21508748263) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10754374134 + 10754374135.

It is an arithmetic number, because the mean of its divisors is an integer number (10754374135).

Almost surely, 2^21508748269 is an apocalyptic number.

It is an amenable number.

21508748269 is a deficient number, since it is larger than the sum of its proper divisors (1).

21508748269 is an equidigital number, since it uses as much as digits as its factorization.

21508748269 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1935360, while the sum is 52.

The spelling of 21508748269 in words is "twenty-one billion, five hundred eight million, seven hundred forty-eight thousand, two hundred sixty-nine".